Fix wordpress problem/s - website looks slightly different in different browsers

this is my website: www.faunaandflora.org

the problem/s:

1.1 in different browsers, specially using macs, the title 'Fauna & Flora' doesn't get properly aligned with the text in the right column. the text in the right column might be aligned using safari but it will be a tiny but up or down using another browser;

1.2 as well, if i press the buttons on the left column the text on the right column will move a bit up or down depending on the browser that i am using.

these aren't very big problems but if you think you can fix them i would be very pleased to pay for your help.

thank you!